Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to travel hitches and particularly to trailer hitches for fifth-wheel type trailers.
2. Description of Related Art
A fifth-wheel travel trailer is essentially a small, self-contained home that may be towed to a desired location by any suitable tractor vehicle, such as a pick-up truck. The forward portion of the travel trailer has a downwardly depending hitch box and downwardly projecting kingpin. This kingpin is sized and adapted to mate with a standard fifth-wheel hitch that is mounted on the tractor vehicle. Thus, the tractor vehicle supports the travel trailer so that its forward end is elevated above the surface of travel, such as a roadway, while the rear portion of the vehicle is supported on a wheel set so that it may travel over the surface.
The substantial weight of the fifth-wheel travel trailer requires proper loading and mounting of the hitch assembly. Where the typical pick-up truck is employed as the tractor vehicle, the fifth-wheel tow hitch receiver is secured in the bed of the pick-up truck above and slightly in front of the rear axle. It is important that the mounting not be located too far forward of the axle to avoid unnecessary bending moments about the axle. Moreover, it is important not to mount the hitch rearwardly of the axle otherwise the tractor vehicle will tend to rear off its front wheels resulting in loss of steering control.
When a long-bed truck is employed as the tractor vehicle, relatively few difficulties are encountered in the proper mounting of a hitch receiver for a fifth-wheel trailer. Recently, though, the popularity of the short-bed pick-up truck has grown. These trucks typically have beds that are 6 to 7 feet in length. Consequently, there is a decreased distance between the rear axle of the pick-up truck and the cab. In such cases, as discussed more thoroughly below, the proper mounting of the hitch receiver results in inadequate clearance between the forward portion of the fifth-wheel trailer and the truck cab. FIGS. 1, 2 and 3, show a typical fifth-wheel trailer 10 attached truck 12, which is a short bed pick-up truck with a hitch 9. In order to keep the hitch receiver and axis A forward of the rear axle 200, as is represented by transverse axis X, a diminished space between the cab 201 of truck 12 and forward portion 11 of the trailer 10 is created. Towing trailer 10 in a straight line causes no problems. However, the turning radius of the combination of truck 12 and trailer 10 is diminished, as is shown in FIG. 3. As is shown in this figure, when the vehicle is making a turn, the corner 11a of forward portion 11 can contact cab 201 which can result in damage to truck 12, trailer 10 or both.
In order to achieve adequate clearance, the tow hitch may be moved rearwardly in the bed, behind the rear axle. However, as noted above, this creates an undesirable and potentially dangerous towing configuration.
Another undesirable situation occurs as the tractor and trailer encounter a series of dips or bumps in the road and the rear of the tractor vehicle and the front of the trailer start a pitching or bucking action as one dip in the road is encountered after another. This pitching action is not only bad for the components of the two vehicles; it is dangerous. Accordingly, a need has arisen for alternative mounting assemblies for fifth-wheel trailer vehicles.
It is an object of the present invention to provide a hitch receiver, a hitch extension coupling and a shock absorbing bar to connect a tractor vehicle to a trailer, that allows the trailer to be towed by a short bed type vehicle.
A further object of the present invention is to provide a hitch coupling for a trailer that moves the pivot axis of the trailer rearwardly of the tractor vehicle while maintaining the load point of the trailer forward of the tractor vehicle""s rear axles.
Another object of the present invention is to provide an extension coupling that allows the towing of a fifth-wheel travel trailer by a short bed pick-up truck in a safe manner.
Another object of the present invention is to provide a receiver, an extension coupling and a pitch absorber that allows a short bed pick-up truck to be used to tow a fifth-wheel trailer with diminished risk of damage to either during the towing operation.
Another object is to provide an appropriate hitch receiver for the hitch extension coupling.
Another object is to provide a pitch-absorbing bar to restrict extreme movement of the vehicles.
To accomplish these objects an extension coupling is provided that is adapted to releasably interconnect the trailer to a tow hitch that is located on the tractor vehicle. This extension coupling includes a mount that is adapted to be secured to the trailer, and an elongated arm that has a proximal end portion pivotally secured to the mount, and a distal end portion opposite the proximal end portion. A universal joint with lateral pins is attached to the distal end portion and is adapted to releasably mate with the tow hitch. This allows the trailer to be displaced rearwardly of the tow hitch a distance equal to the length of the elongated arm while at the same time maintaining the loading point on a tractor vehicle forward of the rear axle.
A mount is adapted to be secured to a hitch connecting station on the receiver that has a base plate and a pair of opposed side plates, which are oriented to be fastened to mounting plates that depend downwardly from the front of the trailer. Two cylinders extend down from the base plate of the inner cylinder. They are rigidly secured to the mount. The elongated arm includes a receiver adapted to rotatably receive the truck-mounted hitch. The arm may be structured as a housing, which includes a top wall, a bottom wall opposed to the top wall, and a surrounding sidewall. The arm may be telescoping to adjust the length of the arm.
A universal joint assembly is also provided with the hitch on the towed vehicle. The universal joint assembly engages the tow vehicle receiver when the trailer is attached and is used to resist rotation of the arm relative to the receiver on the tow vehicle. The fore and aft arms of the universal joint connect to the hitch assembly by means of sleeves, which allow the universal joint to pivot on an axis parallel to the tow vehicle. The tow arms perpendicular to the parallel arms seat in the hitch receiver create a perpendicular axis to the parallel axis.
Attached to the truck is a hitch receiver that is a box-like structure with the top and back end removed, The sides of the structure guide the hitch as the receiver is backed under the hitch. Inside the receiver is a pair of xe2x80x9cUxe2x80x9d shaped blocks machined to receive the vertical ends of the universal joint. The xe2x80x9cUxe2x80x9d shaped blocks receive the universal joint appendages as the fifth wheel hitch is lowered onto the hitch receiver. A pair of blocking plates on either side of the receiver swing in over the universal joint appendages securing the universal joint in the xe2x80x9cUxe2x80x9d shaped blocks. A rod passing through a slot in the locking plates moves the locking plates in or out of locking position. A spring-loaded plate engages the rod to secure it in the desired position.
An arm extends rearwardly from the extension coupling to engage the pitch dampener. A pitch dampener is used to reduce the pitching, or up and down bouncing movement, on the rear springs of the tractor vehicle when a series of depressions in the road are encountered.
These and other objects of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of the exemplary embodiment when taken together with the accompanying drawings.